The Equinox is a 3G clamshell phone featuring “eye-catching light effects” that let you associate up to five contacts with a unique effect.

Coming as the US version of Sony Ericsson T707, the Equinox also features a 2.2 inch QVGA internal display, GPS, stereo Bluetooth, FM radio, YouTube access and a 3.2MP camera.

T-Mobile will sell the Sony Ericsson Equinox for $50 with a 2-yr contract agreement.

To celebrate the release of Equinox, Sony Ericsson’s brand ambassador Maria Sharapova will be present at the opening of a new T-Mo store in LA, California, on October 31. A “Maria Sharapova look-a-like contest” will be organized by Sony Ericsson – prizes will include Equinox phones, Sony PSPs and Sony VAIO laptops. More details here.